I would never have ever got to that "tests" directory by myself - I was relying on the Project dialogue that offers to open examples, and had turned on sub directories in there but nothing had shown up..

In your essential GUI code, is there any documentation anywhere as to what from 'test.json' is expected to take? Or perhaps even a 'test.json' anywhere to be down loaded?

(A json array of simple top level json objects I'm guessing?)

I've checked in the console app you've pointed me to, but there is nothing in that directory.

I'll try outputting the console app's file and see if the GUI program can read it.

So, the basic idea is that common to all simple TDataset descendants: define the fields that you want to have in the dataset by calling Fieldsdefs.Add(). Open the dataset, and begin appending records using the sequence Append - populate field values - Post. Finally, when done SaveToFile.